Therapeutic macromolecules (e.g., antibodies) must be formulated in a manner that not only makes the molecules suitable for administration to patients, but also maintains their stability during storage and subsequent use. For example, therapeutic antibodies in liquid solution are prone to degradation, aggregation or undesired chemical modifications unless the solution is formulated properly. The stability of an antibody in liquid formulation depends not only on the kinds of excipients used in the formulation, but also on the amounts and proportions of the excipients relative to one another. Furthermore, other considerations aside from stability must be taken into account when preparing a liquid antibody formulation. Examples of such additional considerations include the viscosity of the solution and the concentration of antibody that can be accommodated by a given formulation, and the visual quality or appeal of the formulation. Thus, when formulating a therapeutic antibody, great care must be taken to arrive at a formulation that remains stable, contains an adequate concentration of antibody, and possesses a suitable viscosity as well as other properties which enable the formulation to be conveniently administered to patients.
Antibodies to the human proprotein convertase subtilisin/kexin type 9 protein (PCSK9) are one example of a therapeutically relevant macromolecule that requires proper formulation. Anti-PCSK9 antibodies are clinically useful for the treatment or prevention of diseases such as hypercholesterolemia and other dyslipidemias, and other conditions. Exemplary anti-PCSK9 antibodies are described, inter alia, in WO 2008/057457, WO 2008/057458, WO 2008/057459, WO 2008/063382, WO 2008/125623, U.S. Pat. No. 7,572,618, WO 2010/077854, US 2010/0166768, and US 2011/0065902.
Although anti-PCSK9 antibodies are known, there remains a need in the art for novel pharmaceutical formulations comprising anti-PCSK9 antibodies that are sufficiently stable and suitable for administration to patients.